#!/usr/bin/env python
# -*- coding: utf-8 -*-
# Copyright 2016 OpenMarket Ltd
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
#     http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import logging
import sys

from twisted.internet import defer, reactor
from twisted.web.resource import NoResource

import synapse
from synapse import events
from synapse.api.errors import SynapseError
from synapse.app import _base
from synapse.config._base import ConfigError
from synapse.config.homeserver import HomeServerConfig
from synapse.config.logger import setup_logging
from synapse.crypto import context_factory
from synapse.http.server import JsonResource
from synapse.http.servlet import RestServlet, parse_json_object_from_request
from synapse.http.site import SynapseSite
from synapse.metrics import RegistryProxy
from synapse.metrics.resource import METRICS_PREFIX, MetricsResource
from synapse.replication.slave.storage._base import BaseSlavedStore
from synapse.replication.slave.storage.appservice import SlavedApplicationServiceStore
from synapse.replication.slave.storage.client_ips import SlavedClientIpStore
from synapse.replication.slave.storage.devices import SlavedDeviceStore
from synapse.replication.slave.storage.registration import SlavedRegistrationStore
from synapse.replication.tcp.client import ReplicationClientHandler
from synapse.rest.client.v1.base import ClientV1RestServlet, client_path_patterns
from synapse.rest.client.v2_alpha._base import client_v2_patterns
from synapse.server import HomeServer
from synapse.storage.engines import create_engine
from synapse.util.httpresourcetree import create_resource_tree
from synapse.util.logcontext import LoggingContext
from synapse.util.manhole import manhole
from synapse.util.versionstring import get_version_string

logger = logging.getLogger("synapse.app.frontend_proxy")


class PresenceStatusStubServlet(ClientV1RestServlet):
    PATTERNS = client_path_patterns("/presence/(?P<user_id>[^/]*)/status")

    def __init__(self, hs):
        super(PresenceStatusStubServlet, self).__init__(hs)
        self.http_client = hs.get_simple_http_client()
        self.auth = hs.get_auth()
        self.main_uri = hs.config.worker_main_http_uri

    @defer.inlineCallbacks
    def on_GET(self, request, user_id):
        # Pass through the auth headers, if any, in case the access token
        # is there.
        auth_headers = request.requestHeaders.getRawHeaders("Authorization", [])
        headers = {
            "Authorization": auth_headers,
        }
        result = yield self.http_client.get_json(
            self.main_uri + request.uri.decode('ascii'),
            headers=headers,
        )
        defer.returnValue((200, result))

    @defer.inlineCallbacks
    def on_PUT(self, request, user_id):
        yield self.auth.get_user_by_req(request)
        defer.returnValue((200, {}))


class KeyUploadServlet(RestServlet):
    PATTERNS = client_v2_patterns("/keys/upload(/(?P<device_id>[^/]+))?$")

    def __init__(self, hs):
        """
        Args:
            hs (synapse.server.HomeServer): server
        """
        super(KeyUploadServlet, self).__init__()
        self.auth = hs.get_auth()
        self.store = hs.get_datastore()
        self.http_client = hs.get_simple_http_client()
        self.main_uri = hs.config.worker_main_http_uri

    @defer.inlineCallbacks
    def on_POST(self, request, device_id):
        requester = yield self.auth.get_user_by_req(request, allow_guest=True)
        user_id = requester.user.to_string()
        body = parse_json_object_from_request(request)

        if device_id is not None:
            # passing the device_id here is deprecated; however, we allow it
            # for now for compatibility with older clients.
            if (requester.device_id is not None and
                    device_id != requester.device_id):
                logger.warning("Client uploading keys for a different device "
                               "(logged in as %s, uploading for %s)",
                               requester.device_id, device_id)
        else:
            device_id = requester.device_id

        if device_id is None:
            raise SynapseError(
                400,
                "To upload keys, you must pass device_id when authenticating"
            )

        if body:
            # They're actually trying to upload something, proxy to main synapse.
            # Pass through the auth headers, if any, in case the access token
            # is there.
            auth_headers = request.requestHeaders.getRawHeaders(b"Authorization", [])
            headers = {
                "Authorization": auth_headers,
            }
            result = yield self.http_client.post_json_get_json(
                self.main_uri + request.uri.decode('ascii'),
                body,
                headers=headers,
            )

            defer.returnValue((200, result))
        else:
            # Just interested in counts.
            result = yield self.store.count_e2e_one_time_keys(user_id, device_id)
            defer.returnValue((200, {"one_time_key_counts": result}))


class FrontendProxySlavedStore(
    SlavedDeviceStore,
    SlavedClientIpStore,
    SlavedApplicationServiceStore,
    SlavedRegistrationStore,
    BaseSlavedStore,
):
    pass


class FrontendProxyServer(HomeServer):
    DATASTORE_CLASS = FrontendProxySlavedStore

    def _listen_http(self, listener_config):
        port = listener_config["port"]
        bind_addresses = listener_config["bind_addresses"]
        site_tag = listener_config.get("tag", port)
        resources = {}
        for res in listener_config["resources"]:
            for name in res["names"]:
                if name == "metrics":
                    resources[METRICS_PREFIX] = MetricsResource(RegistryProxy)
                elif name == "client":
                    resource = JsonResource(self, canonical_json=False)
                    KeyUploadServlet(self).register(resource)

                    # If presence is disabled, use the stub servlet that does
                    # not allow sending presence
                    if not self.config.use_presence:
                        PresenceStatusStubServlet(self).register(resource)

                    resources.update({
                        "/_matrix/client/r0": resource,
                        "/_matrix/client/unstable": resource,
                        "/_matrix/client/v2_alpha": resource,
                        "/_matrix/client/api/v1": resource,
                    })

        root_resource = create_resource_tree(resources, NoResource())

        _base.listen_tcp(
            bind_addresses,
            port,
            SynapseSite(
                "synapse.access.http.%s" % (site_tag,),
                site_tag,
                listener_config,
                root_resource,
                self.version_string,
            ),
            reactor=self.get_reactor()
        )

        logger.info("Synapse client reader now listening on port %d", port)

    def start_listening(self, listeners):
        for listener in listeners:
            if listener["type"] == "http":
                self._listen_http(listener)
            elif listener["type"] == "manhole":
                _base.listen_tcp(
                    listener["bind_addresses"],
                    listener["port"],
                    manhole(
                        username="matrix",
                        password="rabbithole",
                        globals={"hs": self},
                    )
                )
            elif listener["type"] == "metrics":
                if not self.get_config().enable_metrics:
                    logger.warn(("Metrics listener configured, but "
                                 "enable_metrics is not True!"))
                else:
                    _base.listen_metrics(listener["bind_addresses"],
                                         listener["port"])
            else:
                logger.warn("Unrecognized listener type: %s", listener["type"])

        self.get_tcp_replication().start_replication(self)

    def build_tcp_replication(self):
        return ReplicationClientHandler(self.get_datastore())


def start(config_options):
    try:
        config = HomeServerConfig.load_config(
            "Synapse frontend proxy", config_options
        )
    except ConfigError as e:
        sys.stderr.write("\n" + str(e) + "\n")
        sys.exit(1)

    assert config.worker_app == "synapse.app.frontend_proxy"

    assert config.worker_main_http_uri is not None

    setup_logging(config, use_worker_options=True)

    events.USE_FROZEN_DICTS = config.use_frozen_dicts

    database_engine = create_engine(config.database_config)

    tls_server_context_factory = context_factory.ServerContextFactory(config)
    tls_client_options_factory = context_factory.ClientTLSOptionsFactory(config)

    ss = FrontendProxyServer(
        config.server_name,
        db_config=config.database_config,
        tls_server_context_factory=tls_server_context_factory,
        tls_client_options_factory=tls_client_options_factory,
        config=config,
        version_string="Synapse/" + get_version_string(synapse),
        database_engine=database_engine,
    )

    ss.setup()
    ss.start_listening(config.worker_listeners)

    def start():
        ss.get_datastore().start_profiling()

    reactor.callWhenRunning(start)

    _base.start_worker_reactor("synapse-frontend-proxy", config)


if __name__ == '__main__':
    with LoggingContext("main"):
        start(sys.argv[1:])
